[llvm] r334993 - Revert "Simplify blockaddress usage before giving up in MergeBlockIntoPredecessor"

[Xin Tong via llvm-commits]

On Mon, Jun 18, 2018 at 5:52 PM Shoaib Meenai <smeenai at fb.com> wrote:
>
> You should use the revert instructions in http://llvm.org/docs/GettingStarted.html#for-developers-to-work-with-git-svn so that you end up with an SVN revision number instead of a git hash in your commit message.

Thank you for letting me know, Shoaib. Another thing is to make sure
to run check-all, instead of just check-llvm before committing.
-Xin



>
>
>
> From: llvm-commits <llvm-commits-bounces at lists.llvm.org> on behalf of Xin Tong via llvm-commits <llvm-commits at lists.llvm.org>
> Reply-To: Xin Tong <trent.xin.tong at gmail.com>
> Date: Monday, June 18, 2018 at 4:25 PM
> To: "llvm-commits at lists.llvm.org" <llvm-commits at lists.llvm.org>
> Subject: [llvm] r334993 - Revert "Simplify blockaddress usage before giving up in MergeBlockIntoPredecessor"
>
>
>
> Author: trentxintong
>
> Date: Mon Jun 18 16:20:08 2018
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> New Revision: 334993
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>
>
> URL: https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_viewvc_llvm-2Dproject-3Frev-3D334993-26view-3Drev&d=DwIGaQ&c=5VD0RTtNlTh3ycd41b3MUw&r=o3kDXzdBUE3ljQXKeTWOMw&m=h3HKGcX0-trl93_e29E2Foso6t9GNBoAdDczCRJmg1I&s=2qYaafNd6i42bQ2Xwvnip27p30pkuvnKpL5QywXf_A8&e=
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> Log:
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> Revert "Simplify blockaddress usage before giving up in MergeBlockIntoPredecessor"
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>
>
> This reverts commit f976cf4cca0794267f28b54e468007fd476d37d9.
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>
>
> I am reverting this because it causes break in a few bots and its going
>
> to take me sometime to look at this.
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>
>
> Modified:
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>     llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp
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>     llvm/trunk/test/Transforms/SimplifyCFG/dce-cond-after-folding-terminator.ll
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>     llvm/trunk/unittests/Transforms/Utils/BasicBlockUtils.cpp
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>
>
> Modified: llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp
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> URL: https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_viewvc_llvm-2Dproject_llvm_trunk_lib_Transforms_Utils_BasicBlockUtils.cpp-3Frev-3D334993-26r1-3D334992-26r2-3D334993-26view-3Ddiff&d=DwIGaQ&c=5VD0RTtNlTh3ycd41b3MUw&r=o3kDXzdBUE3ljQXKeTWOMw&m=h3HKGcX0-trl93_e29E2Foso6t9GNBoAdDczCRJmg1I&s=1XbIuLzOOqRkP_cDH4VZRJ-egaPnK9G9gjIV3NNh618&e=
>
> ==============================================================================
>
> --- llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp (original)
>
> +++ llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp Mon Jun 18 16:20:08 2018
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> @@ -119,14 +119,7 @@ bool llvm::MergeBlockIntoPredecessor(Bas
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>                                       LoopInfo *LI,
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>                                       MemoryDependenceResults *MemDep) {
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>    // Don't merge away blocks who have their address taken.
>
> -  if (BB->hasAddressTaken()) {
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> -    // If the block has its address taken, it may be a tree of dead constants
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> -    // hanging off of it.  These shouldn't keep the block alive.
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> -    BlockAddress *BA = BlockAddress::get(BB);
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> -    BA->removeDeadConstantUsers();
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> -    if (!BA->use_empty())
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> -      return false;
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> -  }
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> +  if (BB->hasAddressTaken()) return false;
>
>    // Can't merge if there are multiple predecessors, or no predecessors.
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>    BasicBlock *PredBB = BB->getUniquePredecessor();
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>
>
> Modified: llvm/trunk/test/Transforms/SimplifyCFG/dce-cond-after-folding-terminator.ll
>
> URL: https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_viewvc_llvm-2Dproject_llvm_trunk_test_Transforms_SimplifyCFG_dce-2Dcond-2Dafter-2Dfolding-2Dterminator.ll-3Frev-3D334993-26r1-3D334992-26r2-3D334993-26view-3Ddiff&d=DwIGaQ&c=5VD0RTtNlTh3ycd41b3MUw&r=o3kDXzdBUE3ljQXKeTWOMw&m=h3HKGcX0-trl93_e29E2Foso6t9GNBoAdDczCRJmg1I&s=XsJTlGj2vpGLC8P2J7zUGT2-ikb0IuuqssWqqua-CO8&e=
>
> ==============================================================================
>
> --- llvm/trunk/test/Transforms/SimplifyCFG/dce-cond-after-folding-terminator.ll (original)
>
> +++ llvm/trunk/test/Transforms/SimplifyCFG/dce-cond-after-folding-terminator.ll Mon Jun 18 16:20:08 2018
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> @@ -37,7 +37,10 @@ define void @test_indirectbr(i32 %x) {
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> entry:
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> ; CHECK-LABEL: @test_indirectbr(
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> ; CHECK-NEXT: entry:
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> -; CHECK-NEXT: ret void
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> +; Ideally this should now check:
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> +;   CHK-NEXT: ret void
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> +; But that doesn't happen yet. Instead:
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> +; CHECK-NEXT: br label %L1
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>    %label = bitcast i8* blockaddress(@test_indirectbr, %L1) to i8*
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>    indirectbr i8* %label, [label %L1, label %L2]
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>
>
> Modified: llvm/trunk/unittests/Transforms/Utils/BasicBlockUtils.cpp
>
> URL: https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_viewvc_llvm-2Dproject_llvm_trunk_unittests_Transforms_Utils_BasicBlockUtils.cpp-3Frev-3D334993-26r1-3D334992-26r2-3D334993-26view-3Ddiff&d=DwIGaQ&c=5VD0RTtNlTh3ycd41b3MUw&r=o3kDXzdBUE3ljQXKeTWOMw&m=h3HKGcX0-trl93_e29E2Foso6t9GNBoAdDczCRJmg1I&s=uF13OrC35SzcMBdDs5ZpeDqDLkeaz9fhNdujwaEiyMw&e=
>
> ==============================================================================
>
> --- llvm/trunk/unittests/Transforms/Utils/BasicBlockUtils.cpp (original)
>
> +++ llvm/trunk/unittests/Transforms/Utils/BasicBlockUtils.cpp Mon Jun 18 16:20:08 2018
>
> @@ -50,31 +50,3 @@ TEST(BasicBlockUtils, SplitBlockPredeces
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>    SplitBlockPredecessors(&F->getEntryBlock(), {}, "split.entry", &DT);
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>    EXPECT_TRUE(DT.verify());
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> }
>
> -
>
> -TEST(BasicBlockUtils, MergeBlockIntoPredecessor) {
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> -  LLVMContext C;
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> -  std::unique_ptr<Module> M = parseIR(C,
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> -                                      R"(
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> -
>
> -      define i32 @f(i8* %str) {
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> -      entry:
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> -        %dead = extractvalue [1 x i8*] [ i8* blockaddress(@f, %L0) ], 0
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> -        br label %L0
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> -      L0:
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> -        ret i32 0
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> -      }
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> -      )");
>
> -
>
> -  // First remove the dead instruction to empty the usage of the constant
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> -  // containing blockaddress(@f, %L0)
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> -  Function *F = M->getFunction("f");
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> -  auto BBI = F->begin();
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> -  Instruction *DI = &*((*BBI).begin());
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> -  EXPECT_TRUE(DI->use_empty());
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> -  DI->eraseFromParent();
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> -
>
> -  // Get L0 and make sure that it can be merged into entry block.
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> -  ++BBI;
>
> -  BasicBlock *BB = &(*BBI);
>
> -  EXPECT_TRUE(MergeBlockIntoPredecessor(BB));
>
> -}
>
>
>
>
>
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